Amphibian propulsion mechanism



W. C. BAKER AMPHIBIAN PROPULSION MECHANISM June 8, 1954 Filed Nov. 10, 1949 4 Sheets-Sheet l FIG. 3;

INVENTOR. WI Hard 0. Baker ATTORNEY June 8, 1954 w. c. BAKER AMPHIBIAN PROPULSION MECHANISM 4 Sheets-Sheet Y 2 Filed Nov. 10, 1949 35 FIG.4.

IN VENTOR" WILLARD c. BAKER ATTORNEY June 8, 1954 w. c. BAKER 2 6 0 AMPHIBIAN PROPULSION MECHANISM Filed Nov. 10. 1949 4 Shee'ts-Sheet 3 l N INVENTOR II N WILLARD C. BAKER I l BY W ATTORNEY W. C. BAKER AMPHIBIAN PROPULSION MECHANISM June 8, 1954 4 Sheets-Sheet 4 Filed Nov. 10, 1949 FIG.9.

VIIIIIIIIJ INVENTOR WILLARD G. BAKER ATTORNEY Patented June 8, 1954 UNITED STATES PATENT OFFICE 6 Claims. (Cl. 1151) (Granted under Title 35, U. S. Code (1952),

see. 266) The present invention relates to endless chain propellers, and more particularly to a propulsion mechanism for amphibian craft.

Prior fluid impellers for track laying amphibian vehicles have two major disadvantages. First, they attempt to adapt the impellers to both fluid and land travel. This results in breakage and fouling when light weight thin section impellers are used, and in loss of effective propulsion when impellers were made heavy enough to avoid breakage. Secondly, it has been proposed to attach paddle members to the outside rim of an amphibian traction belt. This arrangement creates so much drag during the return travel of the belt that effective propulsion is critically diminished.

The present invention avoids these and other disadvantages by providing a series of inwardly projecting fluid impeller blades of true hydrofoil section arranged on a traction belt between two spaced-apart series of outwardly projecting land treads.

One object of the present invention is to provide a combined track and impeller system for amphibian craft in which the impeller blades are of true hydrofoil section with a base of adequate area to augment the load-bearing surface of the land treads.

A further object is to provide a combined impeller and deflector system that will increase propulsion and avoid cavitation during fluid travel.

An additional object is to provide a train of fluid impeller blades that will serve as an aligning means for the track and as a combined channeling means for the fluid.

Other equally important objects and many of the advantages of the present invention become readily apparent from the following detailed description which illustrates preferred embodiments thereof when considered in connection with the accompanying drawings, wherein:

Fig. 1 represents a side el-evational view, partly in vertical cross-section, of a portion of an endless traction belt embodying the impeller blades.

Fig. 2 a top plan view of a series of the combined impeller blades and land treads, showin the wide base surface of each blade;

Fig. 3 a front elevational view partly in crosssection of one of the novel impeller blades; taken on line 33 of Fig.1.

Fi 4. a bottom plan View showing the extensive surface area of the base of the impeller blade in its operating position between the two series of land treads;

Fig. 5 a velocity component diagram for the modification shown in Figures 7 to 9 inclusive;

Fig. 6 a like diagram for the modification shown in Figures 1 to 4 inclusive;

Fig. 7 a side elevation of an amphibian craft, with a portion of the apron cut away to show the arrangement of the upper and lower courses of the endless traction belt;

Fig. 8a side elevation of the cut away portion of the craft of Fig. 7; partly in vertical crosssection.

Fig. 9 a front elevation, partly in vertical crosssection showin the arrangement of the deflector vanes.

In the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is illustrated in Figs. 1 to 4 inclusive 2. preferred embodiment of the present invention comprising the novel impeller blade track-sections 30, the treads 40, the track links 49 and their connector links 4!, and in Figures 5 to 9 inclusive a preferred modification thereof comprising deflector vanes ill.

The combined hydrofoil impeller blade track section 30, includes the curved leading edge or lip 35, the curved leading face 33, the curved back surface 32, the broad base surface 3|, and the curved side walls 34. The side walls 34 and lip 35 are formed to also serve as a reinforcing web for the impeller blade 30 and for its foot portions 36.

As shown in Fig. 9, the blade 30 functions as a center guide and aligning means for the moving track as it travels between the opposite rows of bogie wheels 20, when in operation, so that side walls 34 are in sliding contact with the opposed inner faces of bogie wheels 26. The reinforcing web also increases the rigidity of blade section 39 and acts as a means for channeling fluid into the impeller surface 33.

The foot portions 36, the track pin housing 31, the web portion formed of the side walls 3%, the lip 35 and base 3! are all preferably of integral construction in blade 30, and may be of welded or cast metal. The grouser elements or land treads is are also preferably integral with foot portions 36 as shown in Fig. 3.

The base 3| includes track pin housing 31, resilient bushings 38, and track pins 39. Bushings 38 are made of a flexible material such as rubber or plastic or the like, and are formed in a series of annular or doughnut-like sections adapted to be held in place under pressure between track pi or shaft 39 and housing 31.

Biishings 38 provide cushionin and also prevent resilient track stretching. They afford improved dampening means at each track pin 39, so

that any hysteresis eifect occurring between the contacting surfaces of rubber bushings 38 and the metal surfaces of shaft 39 and housing 37, will act to retard sudden motions of each track pin and track section during rough travel. The rubber or plastic material in bushings 33 also acts under compression to maintain a seal between housing 3'1? and pin 39. This arrangement efiectively reduces noise, vibration, and wear.

Track sections 30 are connected with each other by means of connector links 4!. Each link 4| is provided with a resilient space snubber 42 and a connector hole 46 at one end and a ser rated hole 43 at its other end. Each of track pins 39 are provided with a serrated portion 44 so that when assembled, portion 44 will be fixed by a forced fit in serrated hole 43 to one end of link 4|. This provides a rigid connection between track pin or shaft 39 and connector link 48. The other end of each connector link :3! is rigidly mounted to each track section 30 by means of tapered pins 45 as shown in Fig. 3.

Pins 45 are fitted through foot portions 35, holes 4! in links 4|, track links 49, and are tightened in position by nuts 52 as shown in Fig. 3. Track cover plate 53 seals off nut 52 and prevents fluid and dirt from fouling the rotatable connection between link 49 and pin 39. Connector links 4! are further rigidly connected to track sections 38 by means of interfitting connector wedge portions 48 and 50 as shown in Fig. 1. Track links 49 are mounted for sliding movement on foot portions 36 and on pins 39 by means of splines or tongue and groove engagement as shown at 5| in Fig. 1.

When the endless track is completely assembled the resilient space snubbers 42 (Fig. 1) movide cushioning and sound dampening means between the sections 30, and further serve as a bridge between sections 33 for the travel of bogie Wheels 2! thereover as shown. in Fig. l. Vibration of the bogie wheels 20 as they pass from one to another of track sections 30 is thereby effectively reduced.

As shown in Fig. 1, it is preferred to position the curved face 33 so that its chord C is at an angle A that is within the approximate range to 30 from the normal line N. The radius R of the curve 33 varies in accord with size of the craft and other design factors. This same range also applies to the positioning of the curved face 13 of deflection vanes 10 where radius is also governed by size of craft, spacing of vanes, and other known but changing factors.

A preferred modification of my novel propulsion mechanism is illustrated in Figures 7 to 9 inclusive, wherein a series of deflector vanes it are arranged on hull Bil in cooperating relationship with the hereinbefore described novel impeller blades 35. proved amphibian is illustrated in Fig. 7 as it appears in position when afloat, showing arrangement of the hull 89. Here it will be seen that.

A preferred form of the imforward propulsive force which assists in propelling the amphibian.

The propulsion mechanism includes an idle sprocket 22, a drive sprocket 23, a series of idle guide rollers 24, and a series of bogie wheels 23. Trained about these sprockets, rollers and wheels is an endless traction belt 25. Provided on the exterior face of the belt is an endless series of impeller blade track sections 30 including treads 4% which engage the ground and support the amphibian when the latter is traveling on the land, and the blade surfaces 33 which engage the water and propel the amphibian when afloat.

As shown in Figures 8 and 9 the novel fluid deflector vanes 19 are of hydrofoil conformation and are preferably afiixed to the lower portion of hull Si] by attaching means such as is indicated by plates ll and bolts '52. Vanes is also serve as supports for bogie wheels 28 which are preferably mounted thereon by shafts 2i, and held in cooperative arrangement with impeller blades 33 as preferably illustrated in Figs. 5 and 6.

Fig. 5 comprises a velocity diagram illustrating an interpretation of the theory involved in the modification or" the present invention as illustrated in Figs. 7 to 9 inclusive, and Fig. 6 comprises a like diagram with respect to the modification illustrated in Figs. 1 to 4 inclusive.

As shown in Fig. 5, the travel of the endless track over its lower course creates a suction which induces the water to flow in at the sides of the hull in a direction approximately normal to the direction of travel of the hull, and at a lateral velocity of V10, which of course has a longitudinal velocity of zero. V10 is next diverted downwardly toward vane 78 at a velocity of V11. The vanes it move with the hull at a forward velocity of V12 relative to V11 and V10. This causes the water to engage the vane ii! at a velocity and direction of V13, and to leave vane at a velocity and direction of V131, relative to vane it, but at a direction and velocity of V 131+ J 12:?14 relative to V10.

The water next engages impeller blade 33 at the direction and velocity of V14 relative to V111, and then leaves blade 39 at the direction and velocity of V15 relative to blade 3%.

Blades move rearwardly along the lower or propulsion course of the endless track at a horizontal direction and velocity of V11, relative to the hull velocity V12.

As previously described herein, the water when leaving blade has a direction and velocity of V15 relative to the blade 33. However its direction and velocity relative to V10 is V13, which is equal to fwd-V17. Accordingly it will now be seen from Fig. 5 that V111 is equal to the downward component of V13. It will further be seen from Fig. 5 that the longitudinal component of V111 is V19. The thrust produced thereby is pro portional to the second power of the absolute velocity component V19.

In Fig. 6, V10 is also the lateral velocity of the water sucked into the hull by the rearward travel of the track, but in this embodiment, its downwardly diverted velocity is V1, and V1 is the direction and velocity relative to V10 at which the water engages blade 38.

V5 is the direction and velocity of the water relative to blade 30, at which the water leaves blade 30;

V7 is the velocity relative to the hull, at which blade 30 travels in the rearward lower course of the endless track, and is indicated in the lower diagram in Fig. 6. As shown in the upper diagram in Fig. 6, V7 is also the horizontal component of the velocity of the water as it engages blade 30 relative to the rearward travel of blade 30.

In comparing the diagrams of Fig. 5 with those of Fig. 6 it will be seen that with the addition of vane in Fig. 5, that V19 Will materially exceed V17. in contrast to Fig. 6 where without vane 10, V9 must always be less than V7, even though the novel hydrofoil section and arrangement of blade 30 provides a material increase in thrust efficiency over prior art propulsion means; and is in itself a valuable advance in the art.

From the foregoing it will be seen that in operation my novel impeller blade track sections 30 effectively increase the efficiency of track 25 in the following ways: by providing greater area and strength to tread portions 40; by serving as an improved guide for track 25; by providing improved water channeling and propelling means; by positioning blades 30 between treads 40, thereby increasing thrust and reducing noise and cavitation, and avoiding damage to the blades when crossing reefs and other obstructions. It willfurther be seen that the addition thereto of the novel deflector blades 10 afford a valuable increase in thrust eiflciency as illustrated in Figs. 5 and 6.

In operation these vanes in cooperation with impeller blades 30 provide the following additional advantages: high thrust and high power efliciency by delivering high velocity exit water from low track velocity; minimum counter-thrust, and an additionally effective utilization of entire length of track 25 as shown by the leading vane 16 in the extensive series of vanes 70 and blades 30 as illustrated in Fig. 7.

As shown in Fig. 9, vane 10 is preferably fixed to apron 60 of hull 80 by stud means 18 and support means 71. The opposite stud 18 is held in hull 86 by the bearing assembly 19 which is supported by resilient bushing 91. This bushing 9'1 is preferably of rubber and is arranged to act as a torsion spring in cooperating in the support of hull 80 during land travel. The attaching plate I! of vane 10 may be preferably fixed to and adjustably positioned on assembly 19 by adjustable holding means, such as bolt and slot means indicated at '12, so that the angleof vane I0 may be adjusted within a limited range.

Related hereto are the following concurrently r filed co-pending applications of: Willard C. Baker and William Nicholas for Amphibian Control Mechanism," Serial Number 126,656; Emil S. Cigledy, for Deflector System, Serial Number 126,660; Edward J. Eyring, for Deflector Control, Serial Number 126,653; Edward J. Eyring for Deflector, Serial Number 126,654; and Edward J. Eyring for Deflector Mechanism, Serial Number 126,652.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

While only preferred embodiments of this invention have been disclosed, it is obvious that various modifications thereof are contemplated and may be resorted to by those skilled in the art without departing from the spirit and scope of the appended claims.

What is claimed is: v

1. In combination, in a mechanism for propelling an amphibian craft: an endless traction belt; two spaced apart rows of treads on said belt for travel on land; and a series of fluid impeller blades for travel in a fluid, so positioned on said belt between said two rows of treads, that said blades project inwardly with respect to said belt.

2. In combination, in an amphibian craft, a mechanism for propelling said craft in a fluid: said mechanism including an endless belt assembly adapted to be driven along a lower fluidengaging course and thereafter along an upper return course; two rows of spaced-apart outwardly projecting treads on the traction surface of said belt for travel on land; a row of fluid impelling blades projecting inwardly from the opposite surface of said endless belt and positioned between said rows; deflector vanes carried by said craft adjacent the points of said blades to cause the flow of said fluid to be directed to said blades; a pair of bogie wheels rotatably mounted on each of said vanes and positioned to engage said opposite surface of said assembly on each side of said blades; and apron means on said craft enclosing the outer side of said upper course.

3. In combination, in a mechanism for propelling an amphibian craft: two spaced apart series of bogie Wheels, an endless traction belt arranged for operation on said bogie wheels, two spaced apart rows of treads projecting outwardly from said bogie wheels on said belt for travel on land, and a series of fluid impeller blades for travel in a fluid projecting inwardly toward said bogie wheels between said rows of treads, and means carried by said blades to cause said blades to present a hydrofoil contour to the flow of said fluid between said two series of wheels.

4. The combination of claim 3 wherein said series of blades carries means cooperating with said bogie wheels to operate as a center alignment guide for each of said belts in said mechanism between said series of bogie wheels.

5. The combination of claim 3 wherein said series of blades carries sufficient base area providing means to cause said blades to operate as additional load bearing surfaces between said rows of treads for land travel over soft and irregular surfaces.

6. Apparatus for propelling an amphibian craft, said apparatus including in combination: an endless belt-like assembly arranged to be driven along a first lower positioned fiuid-engag ing course and thereafter alon a second, upper positioned return course, said belt having two spaced apart rows of treads, impeller blades on said belt between said rows of treads projecting inwardly from said first course toward said second course for travel in a fluid, and deflector guide means carried by said craft adjacent the inward end of said blades on the fluid-engaging course for directing the flow of said fluid to said blades along said first course in a manner whereby the horizontal component of velocity of said flow will act to increase the propulsive effect of said blades on said craft.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,404,490 Hait July 23, 1946 FOREIGN PATENTS Number Country Date 121,151 Germany June 6, 1901 

